James Dinwiddie

James Dinwiddie (born 8 December 1746 in Dumfries – died 19 March 1815 in Pentonville) was a Scottish physicist, astronomer, inventor and natural philosopher. He was an early example of a science popularizer, giving tours and experimental demonstrations across England and Ireland. He travelled and resided in Calcutta, India and travelled to China along with Lord Macartney as part of the Macartney Embassy to lecture on physics and promote British astronomical techniques.

Life and work Dinwiddie was born on 8 December 1746 in Tinwald near Dumfries where his parents John Dinwoody and Catharine Riddick were farmers. One of five children, he was born shortly after the death of his father. He worked on the farm and gained an interest in mechanical devices, building a wooden clock even as a young boy. He went to school at Dumfries Academy where he studied mathematics and languages and continued his studies at the University of Edinburgh. The family hoped he would join the church but he took an interest in science. After his studies he spent some time as a teacher of mathematics and natural philosophy (physics mostly). Around this period he took a special interest in surveying and navigation. In February 1778 he received a Master of Arts from the University of Edinburgh and he was invited to teach at Ayr by Professor Dugald Stewart. In his lectures he demonstrated experiments, instruments and emphasised the use of mathematical principles involved in physical laws and gave examples to support his view:

Returning from China, Dinwiddie met Sir John Shore, Governor-General of Bengal, stayed on in Calcutta and continued his researches. In 1795 he gathered subscriptions to lecture to nearly 180 ladies and gentlemen in Calcutta and raised rupees 100 for it. Some of the surveying instruments carried by Dinwiddie to China such as the chain were then sold in Calcutta and used by William Lambton in his initial surveys in southern India.

In August 1795 Dinwiddie was appointed to assist the Board of Trade on matters of science for a salary of 500 rupees a month for a year; but this was not extended. He also constructed a voltaic pile with which he claimed to have "treated" patients with palsy and rheumatism with electric shocks.

Meanwhile, Dinwiddie was appointed as professor of natural philosophy at the Fort William College in 1801. He also conducted public as well as private lectures and demonstrations for Europeans and some of the Indian elite. He trained the Indian students Hurry Mohun Thakoor and Gopee Mohun Deb in astronomy in 1795. His students included the surveyor James Rennell. Dinwiddie advised the East India Company, prepared the chemists kit carried by Francis Buchanan for his survey of Mysore and manufactured nitrous acid for use in the hospital at Calcutta. Dinwiddie was also in correspondence with Joseph Hume who was his agent and supplier of chemicals in London. In 1796 he visited Madras where he met the Governor, Lord Hobart. He was elected to the Asiatic Society of Bengal.

He believed that without mathematical reasoning one could not dig deeper in science. He said:"Only in those parts of the science which have been mathematically considered, that natural philosophy can boast of having carried on her investigations with certainty, success and utility."He believed that without mathematically described knowledge, one could not go beyond a schoolboy's understanding of science.

Dinwiddie was never married but he acknowledged a daughter Ann, named after her mother Ann Muir.